The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘C++’ Category

How isotopp became the online handle of Kristian Köhntopp

Posted by jpluimers on 2022/06/09

Like me, [Archive.is] Kristian Köhntopp is a nerd.

Unlike me, Kris bumped into character encoding issues for just about all his digital life. That started about the same time as mine, but again unlike me: he was way more involved in the technical aspects of it.

First a series of Tweets:

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Posted in ASCII, C++, Development, Encoding, EPS/PostScript, Font, ISO-8859, ISO8859, Power User, Software Development, Times New Roman | Leave a Comment »

Tesseract (software): amazing command-line OCR tool

Posted by jpluimers on 2022/05/13

A twitter post blasted me away by showing the results of Tesseract (software) – Wikipedia doing perfect OCR on an image from a twitter post:

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Posted in C++, Color (software development), Development, OCR, Power User, Software Development, Tesseract | Leave a Comment »

When floating point code suddenly becomes orders magnitudes slower (via C++ – Why does changing 0.1f to 0 slow down performance by 10x? – Stack Overflow)

Posted by jpluimers on 2022/01/26

When working with converging algorithms, sometimes floating code can become very slow. That is: orders of magnitude slower than you would expect.

A very interesting answer to [Wayback] c++ – Why does changing 0.1f to 0 slow down performance by 10x? – Stack Overflow.

I’ve only quoted a few bits, read the full question and answer for more background information.

Welcome to the world of denormalized floating-point! They can wreak havoc on performance!!!

Denormal (or subnormal) numbers are kind of a hack to get some extra values very close to zero out of the floating point representation. Operations on denormalized floating-point can be tens to hundreds of times slower than on normalized floating-point. This is because many processors can’t handle them directly and must trap and resolve them using microcode.

If you print out the numbers after 10,000 iterations, you will see that they have converged to different values depending on whether 0 or 0.1 is used.

Basically, the convergence uses some values closer to zero than a normal floating point representation dan store, so a trick is used called “denormal numbers or denormalized numbers (now often called subnormal numbers)” as described in Denormal number – Wikipedia:

In a normal floating-point value, there are no leading zeros in the significand; rather, leading zeros are removed by adjusting the exponent (for example, the number 0.0123 would be written as 1.23 × 10−2). Denormal numbers are numbers where this representation would result in an exponent that is below the smallest representable exponent (the exponent usually having a limited range). Such numbers are represented using leading zeros in the significand.

Since a denormal number is a boundary case, many processors do not optimise for this.

–jeroen

Posted in .NET, Algorithms, ARM, Assembly Language, C, C#, C++, Delphi, Development, Software Development, x64, x86 | Leave a Comment »

Valetudo | Cloud-free control webinterface for Xiaomi vacuum robots

Posted by jpluimers on 2022/01/04

[Wayback] Valetudo | Cloud-free control webinterface for vacuum robots

Valetudo is a standalone binary which runs on rooted Vacuums of the Xiaomi ecosystem and aims to enable the user to operate the robot vacuum without any Cloud Connection whatsoever.

You can even use it to make a WiFi heat map of the floors in your home: the Valeroni app can do that for you.

The Valeroni app is open source too: [Wayback/Archive.is] ccoors/Valeronoi: A WiFi mapping companion app for Valetudo

Via [Archive.is] Kristian Köhntopp on Twitter: “Paging @sys_adm_ama: … Alternative Firmware für Robot-Staubsauger … Alternative Firmware für Robot-Staubsauger verwenden, um das Wifi im Haus zu mappen (und Staub zu saugen)”

–jeroen

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Posted in C++, Development, Hardware, LifeHacker, Power User, Software Development, WiFi | Leave a Comment »

The Charlie Calvert “Here’s to Good Friends and New Adventures” article

Posted by jpluimers on 2021/10/14

Since this contains a list of contains from back then (20+ years ago!), I save it for future reference: [WayBack] Here’s to Good Friends and New Adventures

I would like to make a very short list of the other people at Borland who I have had the privilage of working with very closely. These people are Jason Sprenger, Xavier Pacheco, Steve Teixeira, John Kaster, Lar Mader and Rich Jones. Each of these people I worked with every day over a period of years, and they never showed me anything but the very best and most admirable human traits. I hope I am so lucky as to work with such fine people again in my life.

As for all the others, there is no way even to begin to thank them. A few of these people are Karen Giles, Lino Tadros, Steve Trefethen, Christine Ellis, Paolo Ciccone, Yolanda Davis, Blake Stone, Bruneau Babet, Dave Marancik, Anders Ohlsson, Dave Powell, Claudio Briceno, Joe Manzone, Terri Bartos, Dave Wilhelm, Andrea Ginsberg, Jason Vokes, Ludo Neveu, Martin Pamdeth, Martin Raim, Ernesto Franchini, Edwin Desouza, Zack Urlocker, Rosemary Abell, Robert Warren, Scott Bussinger, Richard Morris, Paul Beach, Jeremy McGee, Nimish Vora, Michael Swindell, Lorie Hull, Kendyll Upstrom, Kari Gallant, Allen Bauer, Josh Dahlby, Jose Rubens, John Thomas, John Williams, J.D. Hildebrand, Hizo Jozsef, Goran Kallmark, Ben Riga, George Cross, Gary Benner, Fred Felman, Erik Jakowitz, Danny Thorpe, Craig Farrell, Claudia Currie, Bill Weber, Lance Devon, Robert West, Amber Hein, Richard Kubat, Jeff Peters, Ellie Peters, Krystyna Niedzwiedzka, Kathy Berkland, Kelly Welty, Tom Lam, Nester Miranda (and Carlos!), Dana Kaufman, Pawal Ksiezyk, Jim Wright, Lori and Ellen from travel, Sergey Orlik and many others who I just don’t happen to recall right now, or who I liked very much but only met a few times.

I’m also indebted to Ray Kanopka, Mark Miller, Dick Malley, Dan Horn, Taco Oosterkamp, Bob Swart, Ann Lynnworth, Marco Cantu, Jeroen Pluimers, and many more who worked in the Borland community and brought me great joy. It’s amazing to consider how many talented and remarkable people have been drawn to this company.

jeroenhttps://www.facebook.com/groups/137012246341854/permalink/2895795467130171/

Posted in Borland C++, C++, C++ Builder, Delphi, Development, Pascal, Software Development, Turbo Pascal | Leave a Comment »

 
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